Considerations for wire trellis systems and loading: wind, snow, rain

Green Wall Loading Advice

The load placed on the green façade and the implications for design

The following information is intended as advice only. For most domestic green wall applications there should be no need for any of the following considerations. It is mainly for the large scale commercial projects that further advice may be needed.

We strongly recommend that green facades of this type should be designed with advice from structural engineers depending on the type of design wanted and the architecture of the building.

As a brief introduction the following are points to consider;

The weight of the plant

The weight of the planting on green walls can vary enormously - anything between 1 and 50 Kg/M2 of plant area.
This weight is also influenced by the location of the façade, the quality of the soil, the vigor of the plants used and the maintenance of the plants.

The wind load exerted on the façade

Wind load is a result of direct pressure of wind on the structure - which must be treated as a solid surface. Wind resistance is least on climbers that have a shallow profile. When there is a considerable amount of foliage and branches, there can be considerable stress placed on the supports. If the façade is placed in a position that is extremely vulnerable to high winds, this additional growth must be removed to prevent the supports from potentially being damaged.

Dew, rain and snow

The structure must be able to withstand the additional weight of dew, rain and snow loads. The following must be calculated for the extra loading.

1. Deciduous Plants - Plant weight x 2

2. Evergreen Plants - Plant weight x 3

The weight of the structure

The weight of the structure itself needs to be calculated based on the height above the ground. If the structure is going to be taking the weight by supports at the top and the bottom, then the top supports need to be able to take the whole load plus half the wind load, whilst the bottom supports need to be able to support half the wind load.